//是否登陆过滤类
package com.sy.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class AuthenticationFilter implements Filter {
	String url="/";

	
	public void destroy() {
	}

	
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException,
			ServletException {
		HttpServletRequest req =(HttpServletRequest)request;
		HttpServletResponse res =(HttpServletResponse)response;
		HttpSession session=req.getSession();
		if(session.getAttribute("admin.username")==null){
			res.sendRedirect(req.getContextPath()+url);	
			return ;
		} 
		chain.doFilter(request, response);			
	}


	public void init(FilterConfig config) throws ServletException {
		url=config.getInitParameter("url");
	
	}

}
